This pamphlet also lists nominal and standard sizes for all Southern Pine products.
The Southern Forest Products Association (SFPA) publishes a comprehensive pamphlet, “The Southern Pine Use Guide,”. Voluntary Product Standard PS 20-20 American Softwood Lumber Standard. These differences in width are the same for boards. This is common knowledge for the experienced lumber user and is the result of the fact that wider lumber shrinks more in width than the narrow lumber during drying. The 2×4’s and 2×6’s are ½” less than nominal in width and the 2×8, 2×10’s and 2×12’s are ¾ of an inch less than nominal. The most commonly available dimension lumber sizes are 2×4 through 2×12. The Nominal and standard sizes of lumber can be found in the Voluntary Product Standard PS 20-20 American Softwood Lumber Standard. This standard lists the nominal and minimum dressed sizes for all categories of structural and nonstructural lumber. The length of dimension lumber can range from 6 to 24 feet. Technically, you can define dimension lumber as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick and from 4 to 12 inches (10.2 to 30.5 centimeters) wide. Framing of buildings commonly uses the construction lumber and that is where the name framing or Dimensional lumber comes from. Softwood Dimension Lumber Sizesĭimension lumber is lumber cut and finished S4S, (surfaced four sides) and is available in standardized sizes. In most places, you should see both the nominal and actual dimensions on the label or other sign at the point of sales. The label should also state “the actual or minimum measurements.” This is if the label or other sign clearly states that the size given is a nominal size. According to the American Wood Council, the National Institute of Standards and Technology permits stores to label lumber with nominal dimensions.
The size labels now have a new requirement. However, there was one change that the courts mandated. The courts eventually found that the use of nominal lumber sizes was long-standing. Builders, engineers, architects, buyers, and sellers are familiar with the differences between nominal and actual lumber sizes. The courts eventually found that the US of lumber sizes is in nomina l inches in and in millimeters in other countries. They also brought a few hardware and building supply chains for false advertising by selling lumber that they maintained, was undersized. Therefore, you can cut the boards a little smaller than 2×4 inches and still leave it large enough to dress after drying at 1 ½ inches thick and 3 ½ inches wide.Ī few years ago consumer groups brought several lawsuits against some of the big box stores.
1X2 ACTUAL SIZE FULL
Today, modern sawing, drying, and planing technologies are much more precise than cutting green to a full 2×4 inches. Surfacing removes up to an additional ¼ inch from both dimensions. Green southern pine lumber shrinks in width and thickness as it dries. However, after drying and surfacing, the boards became smaller, approaching the now standard 2×4 dimensions of 1 ½ x 3 ½ inches. Originally, a 2×4 was cut as a rough green piece that was close to a full 2 inches thick and 4 inches wide. The actual measurements are the final sizes after drying and surfacing. The derivation of nominal measurements was from a board’s size before its drying and surfacing on all 4 sides. Why are the nominal dimensions of lumber larger than the actual dimensions? This is a well-established industry practice. The reason for the differences is because lumber sizes are traditionally given in their nominal size. The first dimensions are its nominal ones, the second measurements are its actual or minimum dressed sizes. Why isn’t the 2×4 at the lumber yard 2 inches thick and 4 inches wide? The 4×4’s are 3 ½ x 3 ½ and the 1×6’s are ¾ of an inch thick and 5 ½ wide. To the novice do it yourselfer softwood lumber sizes can be hard to understand.
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